Adherent-backed flexible material and method of making same



Sept. 28, 1937. A. FULTON 2,094,428

ADHERENT-BACKED FLEXIBLE MATERIAL AND METHOD OF MAKING SAME Filed Feb. 7, 1936 Patented Sept. 28, 1937 UNITED STATES PATENT OFFICE ADHEREN'I BACKED FLEXIBLE MATERIAL AND METHOD OF MAKING SAME Application February I, 1936, Serial No. 62,799

3 Claims.

My invention relates to adherent-backed, flexible material, and in some of its features, to the making thereof in sheet form, with the adherent surface masked, suitably for commercial handling.

Where it is desired to display signs, symbols, individual-letter legends and the like, on smooth, impermeable surfaces such as mirrors, enameled surfaces of metal or wood, and like supports, common practice runs largely to the use of printed stickers pasted upon the surface, especially where ready removability is desired consistent with rather brief display; and decalcomania transfers or painting are often resorted to for betterment of appearance and for greater permanency of the display. But such displays are destroyable by removal, and their removal is usually troublesome and (according to the nature of the application) either may damage or must damage anyeasily-marred finish of the supports.

Further, where the display is of an out-of-door nature, as upon the bodies of automobiles or on filling station tanks, shipping drums, etc., the extremes of temperature to be met and the inclemencies of rain, sleet, wind, grit, etc., practically preclude satisfactory use, for durable display, of any sort of flexible sticker heretofore available of which I am aware;

After much experimentation and many failures I have succeeded in producing an adherentbacked, flexible-bodiedmaterial, suitable to be readily cut to desired sizes and shapes, for display purposes, the front face 'of which is suitable for the reception of printed matter or for attractive coloration and finish, and the exposed back face of which is strongly adherent to, but is readily removable intact from and without leaving any'residue or trace upon, smooth, clean, impervious supporting surfaces, such as I have above referred to, and which also will permanently retain its cling-capacity (if kept clean) so that the display-article may be used indefinitely, for repeated adherences and removals. And such material I have found, in the quite extensive commercial introduction of it I have already made, to satisfy a large demand that is not served by any other material, either unitary or composite, of which I am aware--especially in field of temporarily-mounted displays.

In general, a primary object of my invention is to produce a quite inexpensive, very durable, and highly useful material having the characteristics I have above referred to and especially well adapted to withstand, both in its own structure and its adhesion to the support-surface, the difficult conditions of out-of-door use on automobiles, etc., above adverted to. A further object is to provide an economical and satisfactory method for producing such a material, and particularly for making it in the form of fiat sheets, suitably masked on the adherent backing face thereof to protect the cling-surface until the display article is to be applied to a support.

Other and further objects of my invention will become apparent hereinafter, from the following description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a perspective view showing, in general, the construction of the masked sheet material; and

Figs. 2 and 3 illustrate, diagrammatically, steps in the process of producing such sheets; Fig. 2

. showing the steps of combining the body layer and the backing layer and rolling the composite material into wound-web form, and Fig. 3 showing the steps of converting such a wound web of the composite material into the desired fiat masked sheets.

In the drawing, Ill indicates a complete masked sheet; I I indicates in general the novel composite material of the character above referred to, which comprises the body layer I2 of flexible material, such as a suitable paper stock, and the backing layer I3, of rubber compound; such backing layer being intimately bonded to the body layer and having a virtually smooth rear face 'constituting the cling surface of the material; and I4 indicates the glazed masking material that protects the cling surface and facilitates commercial handling of the sheetsglazed Holland cloth being preferably used.

The front face I5 of the composite material II is preferably glazedyand also is preferably given a slightly undulating or non-planar surface contour, indicated at I6; all for advantages that will presently appear.

In Figs. 2 and 3, 20 indicates a three-roll calender stack used to apply the backing layer I3 progressively to a long web of the body material I 2, with scrapers or knives 2 I 'trimming the backing layer to the width of web I2. The composite web II passes from this stack 20 to a cooling stack 22, after which it is wound into a composite stock-roll II. It will be noted that no protecting strip is wound into the stock-roll between convolutions of the adherent-backed material.

To convert the rolled web II of composite material into the desired flat masked sheets III, a previously wound roll II and a supply roll I4 of the glazed masking material are jointly unwound as the two webs are passed through suitable straightening and mask-laying equipment 23, and thence the masked web passes to the shear 24 to be cut into the finished, flat sheets iii. In the machine 23, the upper feed-roller 25, which contacts the cling surface of the composite web is desirably relieved to leave only narrow rings of contact, and it is well to let the clinging of the masking material to the composite web draw the masking material from its supply source.

One specific embodiment of my invention that I have found to be suitable for many uses that are not satisfactorily accomplished by any prior material of which I am aware, is made up as follows:

To prepare a suitable cling-coating compound, first-latex crepe rubber, or similar high-grade rubber stock, is mixed with a small percentage of rosin-six pounds of commercial white rosin to one hundred pounds of rubber giving excellent results in the coatings ultimate texture and character-and this mixture is well masticated, preparatory to being applied to the back of the body web, to uniformize the rubber and rosin compound, diffuse any residual air and bring the compound to a plastic enough consistency to take thin, unbroken film form in the calendering operation.

In commercial practice, I find it to be eifective to first masticate the rubber alone, in ordinary breakdown rolls, for about fifteen minutes and, after the rosin in powdered form has been added, to further masticate the mixture for about thirty minutes. Also, to take the resultant compound directly from the breakdown rolls to the calendering machine, in rather small "feeds, warm from the mastication.

The stock mass [3, shown as being fed through the calender rolls in Fig. 2, will be understood to have been treated as thus described.

The stock for the body layer I2 of the composite material should have a rear face with which the backing layer may make a very strong, uniform and intimate bond, stronger than such clinging adherence as the cling-surface can make to a smooth, impervious supporting surface; and I have found that this result is best accomplished by using a body-layer stock that is impregnated with well-disseminated, unvulcanized rubber, and applying the backing layer thereto under calendering conditions that I will describe presently. Rubber-containing papers are commercially available which are well suited to the stated condition; and Patent No. 1,500,500, dated July 8, 1928, discloses a paper of appropriate type.

I find it desirable to apply the backing layer to a depth or thickness of only about eight or ten thousandths of an inch, to body stocks of quite widely varying thicknesses; and in calendering the above-described backing stock 13 to the body Web I2, I have found excellent results to be had by heating the top roll of the calender stack 20 to substantially 200 degrees F.; heating the middle roll to a slightly less temperature, of about 190 degrees F.; and maintaining the lowest roll at a considerably lower temperature, preferably about 130 degrees F; Under these heats the backing film or. layer may be applied very uniformly, smoothly and unbrokenly, and at satisfactory production speed; and under such conditions such excellent bonding of the backing layer is had to the body layer, even where the rear surface of the latter is smooth enough to give small chance for the backing coat to penetrate it interstitially under the calendering conditions, that I believe the tenacity of such bond to be due in part at least to cohesion between the rubber of the backing layer and the rubber content of the body layer-as contrasted with mere surface adhesion of the backing layer to the fibers of the body stock, or interstitial penetration.

When the composite material has cooled, its thin backing film presents a virtually smooth cling-surface, free from crinkling by surface tenvsion; such surface is permanently tacky under extremes of atmospheric temperature ranging from below zero to above 100 degrees F., the compound is characteristically solid and dry, so that 'it cannot be spread or smeared like pasty adhesives and is of such tensile strength and shearstrength that, despite the tenacity with which it will cling to a clean, smooth surface impermeable to air, it may be stripped off of the support surface to which it has been pressure-applied, without leaving any residue or trace upon the latter.

In use, the material is best applied to a suitable support surface by flexing the display-sign or other article progressively into engagement with the support surface, while applying a firm seating-pressure on the front face of the material to drive out air from between the progressively meeting surfaces. And in removing the article, after any temporary display, the body should be flexed away from the support to peel off the article progressively. While the compound of the thin backing layer is quite elastic, when separated from the body layer, it is, nevertheless, what I may term mildly plastic in the sense of a capacity to take surface impressions without immediate elastic return; and suchxa depth of the backing film as I have indicated enables it to make the desired clinging engagement with, and conform to, all parts of surfaces that are only approximately smooth, where irregularities are neither great nor abrupt in ,contour,

I find it to be desirable, for some uses of my novel material, and as well for its economical production, that thefront face of the body stock shall be non-rubber-bearing and shall be glazed for print reception. A pyroxylin glaze, applied to a paper stock that otherwise is rubber-bearing throughout, is satisfactory. Also, additional advantage is had by lightly embossing such surface to make it somewhat undulating or otherwise nonplanar, so that it presents less than its total sur face area in its front contact-plane.

With such a face glazing, the composite material may be wound into the stock-roll I I, without the winding of a temporary masking strip into the convolutions of the roll, and without detrimental sticking of the convolutions together. When so wound, the cling surface of one convolution clings to the glazed surface of the next course, but in the unwinding of the roll for the masking operation shown in Fig. 3, the cling surface progressively detaches itself without trace from the glazed front surface, and its resistance to this stripping is decreased if the glazed face of the body layer is embossed slightly as described.

Since the completed, fiat, masked sheets are protected as to the cling surface, and somewhat strengthened, by the glazed masking cloth, the sheets may be easily handled, cut to shape, printed, or otherwise prepared for display purposes, with facility and without injury; and for ultimate use it is only necessary to progressively strip ofi the masking cloth and flex the clin surface progressively and under slight pressure into contact with a clean, glazed, impervious supporting surface in order to place the desired display.v Removal of the display is best made by 5 progressive detachment, flexing the display-unit as it is peeled off; and between successive uses of the display unit its cling surface is best preserved by masking it again.

If the support surface is clean when the display is applied, repeated applications may be made ,without loss of the clinging efficacy of the backing; and when the cling surface is dirtied by repeated uses or byfingering, cleansing it with a detergent non-injurious to rubber refreshes its clinging capacity; the effectiveness of which appears to involve both vacuum adherence to impermeable surfaces and tacky adhesion, with the vacuum effect furtherable by that pliancy of the material and mild plasticity of the backing film that enables it to be progressively pressed into contact with the entire supporting surface and to conform to non-abrupt curvatures thereof.

My novel material above described is well suited to out-of-door use and under adverse conditions,

vice in signs or legends applied to the enamelled bodies of automobiles, whether for lengthy periods or for frequent change. In such hard service the strong adherence of the cling surface prevents wind-stripping and moisture penetration between the support and the article, when the latter is properly applied; the backing layer is practically unaffected by seasonal wetness, dryness, or temperature changes over a wide range; and the body layer, glazed on its front face and rubber-permeated in rear thereof, is washable, tough and practicallywweathen-proof, as well as being so intimately bonded with the backing as to practically forestall separation of the layers, in use or in applying or removing the article.

While I have herein described in detail the particulars of a specific material, and its manufacture,1that I have found to be highly desirable as excellently embodying features of my invention, it will be understood that this is for purposes of full disclosure and without intent to limit my invention to all of the details thus revealed.

'1 claim:

1. As an article of manufacture, flexible 60 composite sheet material, capable of repeated adhesions to and removals intact-and without trace from smooth clean impervious support surfaces and when so applied capable of withstanding without substantial deterioration or separa- 55 tion from its support a wide range of weai .er conditions including extremes of atmospheric temperatures and inclemencies, comprising a pliant waterproof body layer of fibrous material impregnated throughout with disseminated 00 particles of unvulcanized rubber and bearing a front face glaze of print-receptive compound adhering to said impregnated fibrous material,

and a thin backing layer' of pliant, solid,.

permanently tacky non-spreading compound con- 65 sisting essentially of unvulcanized rubber and its many present uses including satisfactory ser-' thoroughly disseminated rosin in proportion of approximately 6 parts of rosin to 100 parts by weight of rubber, said backing layer being permanently bonded to the entire rear face of said rubber impregnated body layer and presenting a virtually-smooth tacky cling-surface for adhesion to the stated support surface.

2. As a new article of manufacture, an advertising-sign material adapted for repeated temporary adhesions to smooth impervious supporting surfaces such as the finished bodies of automobiles or the like and for removal intact therefrom without trace, comprising a tough waterproofed flexible base of fibrous material impregnated throughout with unvulcanized rubber, one face of said base being coated throughout with a print-bearing glaze-compound adhering to said impregnated fibrous material, and the other face of said base bearing a thin pliant perma nently-tacky backing layer of compound consisting entirely of rubber and rosin and having a permanent bond to the rubber-impregnated base and coextensive in area with the glazed face of the latter, the flexibility of said sign lending itself to progressive applicationto and 'following mild curvatures of the surface on which it is used, and said tacky backing layer bemg substantially unaffected bywidely varying extremes of atmospheric temperature and adapted to maintain its adhesion to the article on which it is used under inclement weather conditions of precipitation, wind, and the like, but permitting removal intact by progressive stripping, for repeated use.

3. The process of making masked flat sheets of adherent-backed material suitable to receive front face printing, comprising the steps of glazing with pyroxylin the front face of a body-stock consisting of a fibrous web impregnated throughout with disseminated unvulcanized rubber and slightly embossing the glazed face to present less than its total surface in its front contact plane: compounding by mastication a rubber and rosin compound consisting of high-grade unvulcanized rubber and rosin in the proportion of 100 parts of rubber to approximately 6 parts by weight of rosin, calendering onto the unglazed surface of said web a thin coating of such compound under calendering heat approximately 200 degrees F. permanently to bond it to the body web for substantial inseparability therefrom and to present a permanently-tacky, virtually smooth rearcling-surface coextensive in area with the glazed face; winding the composite web into .a roll with the cling-surface of each convolution of the backing making adhering engagement with the front contact portions of the confronting glazed and embossed face of the preceding convolution; and subsequently unwinding and flattening the composite web, and while-said web is flat applying masking material to the cling-surface thereof and cutting the masked material into flat sheets.

ASHLEY FULTON. 

